lsp_bad_sample.kt

interface Toy {
    var color: String?
    fun fly()
}

class Plane : Toy {
    override var color: String? = "Blue"
    override fun fly() {
        println("The plane is flying...")
    }
}

class Car : Toy {
    override var color: String? = "Red"
    override fun fly() {
        println("The car is flying...")
    }
}